Ice Stories: Dispatches From Polar Scientists » Phil McGillivary Mon, 15 Nov 2010 20:40:36 +0000 en hourly 1 Listening for Bowhead Whales Mon, 18 Aug 2008 21:04:37 +0000 Phil McGillivary HEALY, ON THE BEAUFORT SEA-- Now that we are aboard the HEALY and settled in, while we slept a survey was done running roughly offshore of Barrow. The principal work along this leg was mapping of the seafloor bathymetry with the ship’s multibeam acoustic system...]]> ABOARD THE USCGC HEALY, ON THE BEAUFORT SEA– Now that we are aboard the HEALY and settled in, while we slept a survey was done running roughly offshore of Barrow. The principal work along this leg was mapping of the seafloor bathymetry with the ship’s multibeam acoustic system, which records echos of sound emitted from the ship and reflected by the seafloor. The return time of the echo, once corrected for water column temperature and salinity, provides depth along the ship’s track. In addition, a series of CTD casts (described in Kevin’s last dispatch) was made to measure water column properties, with additional sensors for measuring fluorescence of chlorophyll in the water column, an indication of the abundance of phytoplankton, the single celled plant life which floats in the oceans, and is an indication of the productivity of the ocean.

Cruise track for HEALY Arctic West Summer Cruise 2008, Leg 4.

The principal work of the first evening included the project of Kate Stafford from the University of Washington, who is retrieving and redeploying moorings placed on the seafloor which are equipped with hydrophones to listen for the sounds of various marine mammals, including seals, walrus, and beluga whales, but with particular emphasis on recording the sounds of bowhead whales (Balaena mysticetus), the sounds of which can be heard at:

The bowhead whales are one of the key marine species in the ecosystem, and important for traditional Inuit culture — their meat and blubber a source of food, and their bones used as sled runners and in house construction. Their baleen (the horny plates in their mouths with which they filter the small shrimp-like euphausiids and copepods — their main food), as shown in the baleen model boat in Day One’s blog, was put to many traditional uses in Inuit culture: as a tough cordage for seal and fish nets; for short lanyards and lashings on sleds; as the tip of dogsled whips; for hunting snares for birds and rabbits; bent into boxes for keeping harpoon heads; made into traditional Inuit snow goggles to prevent snow blindness from glare off snow and ice; as a brow on hats for kayakers to keep spray out of their eyes; as fletching on spears and arrows instead of feathers; and as large knives for cutting ice for igloos, and smaller story knives used to tell stories by ‘drawing’ in snow or dirt. Baleen was also woven together without being cut to form racks hung from the ceiling for general storage, and as floorboards in the traditional semi-subterranean Inuit houses shown in the Day One blogs: a sort of Inuit linoleum! And, in earlier times when warfare between native groups existed, it was also used as plates woven together in the construction of armor. Making of woven baleen baskets was an innovation of the late nineteenth century begun by Barrow resident Charlie Brower.

The bowhead whale is still the principal whale hunted off Barrow. Getting an accurate count of bowhead whales has been a key issue for scientists and the Inuit people for many decades to ensure their proper management and conservation. Preliminary information on the results of the annual aerial survey, along pictures of bowhead whales may be found at: Kate’s hydrophone arrays are deployed offshore of the 100 meter depth line at two locations along the coast in groups of three to allow tracking of whales passing along the coast. Their batteries allow them to operate for a year. In the first day of science, the arrays already deployed from the previous year are retrieved by positioning the ship over their location and generating a specific series of tones which activates an acoustic release. Floats which had remained submerged with the hydrophones are then released from their bottom weights, and the hydrophone and floats drift up to the surface where they are located by a small boat, and passed off to the ship, which then hoists them back onto the deck.

Coast Guard small boat used to retrieve moorings by snagging their floats after release from seafloor.

Once the hydrophones are retrieved, Kate downloads the data from the past year collected by the hydrophones, changes out the batteries and data recording computer hard drives, and later in the cruise will redeploy them. Of concern when retrieving the hydrophones is the ability to find them if there is heavy ice. High resolution (100 meter) satellite images have been requested by the ship showing where the ice is located.

100 meter resolution Radarsat satellite image showing ice concentrations in Beaufort Sea off Barrow, Alaska.

This imagery is from a Radarsat satellite, which is particularly useful as it can see through the ubiquitous fog. In areas where ice concentrations are heavy, hydrophone retrieval can be delayed until the ice has moved away, and the likelihood of retrieving the moorings is more certain: better to wait a bit for conditions to improve than risk a full year’s data.

The principal components of hydrophone mooring array, shown in the photo below being disconnected from the cable by Kate Stafford of the University of Washington and John Kemp of the Woods Hole Oceanographic Institution, are the hydrophone and acoustic release. When the mooring array is redeployed, a float is put over the side first. It is the float which provides the lift to allow the hydrophone and acoustic release to surface, be located by a small boat and retrieved. After the float goes over the side, the hydrophone, and then acoustic release go over, and last of all the weight for the mooring anchor is put over the side. When everything is in the water, the ship is positioned precisely over the desired mooring location, and a manual release is used which, when a rope attached to it is pulled, drops the weight at the correct location, and the entire array is pulled downward to the bottom, where it remains until the ship returns to ‘ping’ the acoustic release with the precise acoustic series of tones to retrieve it a year hence.

Hydrophone and acoustic release mooring components.

Float, weight, hydrophone and acoustic release.

Manual release for weight.

Bowheads were among the whales fairly heavily hunted during the golden days of whaling in the second half of the nineteenth century. Bowhead populations in advance of this period have been cited as about 16,000 animals, although of course, it is impossible to know for certain their historical abundance. The current estimate of the Beaufort-Chukchi-Bering Sea bowhead population is about 8,000-10,000 animals. The numbers of these whales seems to be stable and actually increasing. It is important to get good data on their numbers and habitat use as changes occur in sea ice and ship traffic in the Beaufort and Chukchi Seas.

Each year the bowhead whales migrate south through the Bering Strait in the winter to avoid seas completely covered with heavy ice, so that they can continue to surface and breathe. In the spring they migrate north from the ice edge in the Bering Sea into and through the Chukchi Sea, and many migrate north around Barrow and then east along the coast toward the Canadian arctic and Northwest Passage channels. Maps of the migration routes of some whales tagged by Alaska Fish and Game Department personnel can be seen at As winter arrives, the whales return south along the coast to the Bering Sea.

Interestingly, the bowhead whales are often accompanied north by beluga whales (Delphinapterus leucas), the truly “white whales” of the northern seas. Because of their much smaller size, the belugas cannot easily break through the ice to make breathing holes themselves, and follow the bowhead whales using them as their own ‘icebreaking vessels’ to access more northerly waters in spring. Once in the Beaufort Sea the bowhead whales appear to distinctly prefer the waters closer to shore along the Alaskan North Slope, while aircraft sightings and tagged animals show that belugas remain further offshore in deeper waters, with a fairly distinct separation of habitat use. The fact that bowheads prefer the more nearshore waters along the North Slope makes them potentially more susceptible to increased human activities, and Kate’s project all the more important to contribute to continued monitoring of population levels.

Hunting whales by certain arctic peoples is much more than simply an avocation or way of harvesting food. This is perhaps difficult for outsiders to fully comprehend, but whaling in traditional Inuit and other arctic whaling cultures was, and still is, almost a religious or deeply spiritual enterprise, surrounded with rituals of moral purification and behavioral restrictions. It is still emphatically pointed out that one does not actually hunt whales, but one simply goes hunting for whales: it is the whale that gives itself to the hunter and whaling crew which has strictly maintained the traditions associated with successful whaling. In the arctic this invariably includes, among many other things, widespread distribution of the animals taken to everyone in the community, and other communities as well, practices which are still sustained. George Naekok, who is with us as an Inuit observer on this cruise, has been whaling most of his life.

Barrow resident George Naekok.

Insignia of the Barrow crew which includes George Naekok.
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Sea Ice Dynamics Thu, 14 Aug 2008 16:59:56 +0000 Phil McGillivary HEALY, ON THE BEAUFORT SEA-- One of the things about the sea ice surrounding HEALY that cannot escape your attention is the fact it is neither all white nor flat and level...]]> ABOARD THE USCGC HEALY, ON THE BEAUFORT SEA– One of the things about the sea ice surrounding HEALY that cannot escape your attention is the fact it is neither all white nor flat and level. As shown in the image below, sea ice comes in various colors. After the onset of the cold season the sea freezes and ice covers the surface. Over the course of the winter, storms periodically induce stress in the ice unevenly, breaking it up and moving it around and compressing it together with great force to form ridges. The ridges above the surface are called sails, and those below the surface are called ice keels. It is these features which are of greatest interest to me because it is the ice ridges that are most hazardous to ships and shipping. The ridges are also important to the seals, which have very specific preferences the kind of ice they like in relation to the degree of ridging. The ice ridges are also of interest to the oceanographers on this cruise, who want to understand how these features interact with the winds, currents and tides in the ocean near the Beaufort Sea coast offshore of Alaska’s North Slope.

Ice at sea.

My friend Peter Wadhams has an excellent webpage describing how sea ice forms and decays, and its differences from freshwater ice (to see, click here). As he points out, because of the critical importance of sea ice to planetary climate, it is important for all of us to better understand the dynamics of sea ice. The principal difference of sea ice and freshwater ice is that when it forms initially sea ice includes salt from seawater. This makes it much more flexible and weaker than freshwater ice. But this changes over time as the ice ages and salt is gradually eliminated, so that second year ice which persists over a summer season is both fresher and much harder, particularly on our icebreaking ships when they are forced to break through zones of second year ice.

As a quick backgrounder to how much ice forms each year, and how much of it persists more than one year, I have collected several animations from colleagues which show some of this information. First, here is an animation which shows a typical annual cycle of ice in the Arctic for the first half of the year from Wieslaw Maslowski of the Naval Postgraduate School in Monterey, California:

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Next, here is an animation by Wieslaw of sea ice thickness showing the area off the Canadian Arctic and northern Greenland where second year or multi-year ice commonly persists, and few if any ships, even icebreakers, dare venture:

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Finally, here are two animations by Wieslaw that show cycles of stress in the ice. This one shows shear in the ice, arising from storms that open leads (cracks in the ice), which later close to form ice ridges:

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And this one shows the stress as areas of convergence (blue) and divergence (red) in the pack ice of the Arctic during the winter months:

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Ocean mixing and the effects of storms on sea ice are key components of the research being done by the scientists on this cruise. We are hoping to better understand the mixing of the waters in the Arctic and heat transport from lower latitudes and coastal Arctic waters to the depths of the Arctic Ocean.

The first science operations on HEALY began shortly after everyone was aboard, in the traditional way: by ‘grabbing water.’ This is done using a circular metal frame called a rosette, from which water sampling bottles, called Niskin bottles (named after their inventor) are lowered in an open position into the ocean, and a closure mechanism is electronically activated to capture water from various depths.

A CTD cast.

Niskin bottles.

Along with the Niksin bottles, the rosette includes a CTD. CTD stands for conductivity, temperature and depth; a CTD “cast” (vertical lowering and raising) allows a profile of salinity with depth to be calculated from conductivity of seawater once corrected for temperature and depth. These vertical casts profile the heat content of the Arctic Ocean, and mixing of coastal waters freshened by rivers with the deeper ocean waters. Whereas this is one of the main goals of this cruise, the work is underway: not bad for a first day at sea. And on the morrow the science will start in earnest, hopefully still amid the ever-fascinating ice.

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Off to Sea Wed, 13 Aug 2008 23:44:43 +0000 Phil McGillivary HEALY, ON THE BEAUFORT SEA-- Travel has many pleasures, but as everyone knows, can involve the unexpected...]]> ABOARD THE USCGC HEALY, ON THE BEAUFORT SEA– Travel has many pleasures, but as everyone knows, can involve the unexpected. If you are traveling from Barrow, Alaska, out to meet a ship like the Coast Guard icebreaker HEALY you pretty much have to take a helicopter. The forces associated with the coastal sea ice in Barrow will destroy all attempts at docks or piers, so these simply don’t exist. The shallow coastal waters make small boat landings on the beach possible, but ill-advised: the ocean here is so cold that even a short immersion is really more hazardous than a simple dunk in the ocean you might get elsewhere if the boat swamps in the waves at the beach. In the far north in summer the coast is often shrouded in fog, but there are usually some periods every day when the fog lifts and helicopters are allowed to fly. When we get up in the morning, HEALY is visible just offshore, having arrived from Dutch Harbor in the Aleutians. Our bags are loaded in a truck and we are off to the airport where everyone dons the usually orange, fire-resistant flight suits along with a flight helmet, and are loaded two at a time onto a sequence of Coast Guard helicopter flights for the short trip out to land on HEALY’s flight deck.

Matt in flight suit.

Helicopter on HEALY’s flight deck.

There are three different science projects aboard HEALY coordinated by Chief Scientist Bob Pickart from the Woods Hole Oceanographic Institution, with participation from co-Chief Scientist Harper Simmons of the University of Alaska, Fairbanks, and Kate Stafford from University of Washington. With their post-docs and students our party totals about a dozen people. This includes John Petersen, a participating member of the science party who is also an Alaska high school science teacher, me, Kevin Fall from Intel Research, Berkeley, who is working with me, Barrow Inuit observer George Neakok, and Bob Reiss, a reporter for Outside magazine. Some additional science party members have been aboard HEALY on the transit up from Dutch Harbor preparing some of the science gear.

Chief Scientist Bob Pickart from the Woods Hole Oceanographic Institution.

Co-Chief Scientist Harper Simmons of the University of Alaska, Fairbanks.

Kate Stafford from University of Washington.

After an initial series of helicopter flights, and an interruption while we wait for the fog to lift, we are finally all aboard the ship. In order to give the science party members time to assemble their gear, I fly out on the last flight, right after the special visitors on this trip, the Coast Guard Commandant Admiral Thad Allen and Secretary of Homeland Security Michael Chertoff. Their very presence on the ship is a confirmation of the growing importance of the arctic, both to the interests of the United States and to the planet. After hastily unpacking and settling in, we have dinner and attend an “all-hands” briefing by the Commandant and Secretary Chertoff, who emphasize the importance of the work the HEALY has and will be doing.

From left to right, Homeland Security Secretary Michael Chertoff, Military Aide to the Secretary CAPT Andrew Blomme, HEALY Commanding Officer CAPT Frederick Sommer, and Admiral Thad Allen.

The HEALY is one of three Coast Guard icebreakers. Icebreaking ships come in various classes, which are not internationally standardized. HEALY would be classed as an icebreaker able to break through moderately thick ice. The two other US icebreakers, POLAR SEA and POLAR STAR are classed as “heavy” icebreakers capable of breaking through ice roughly twice as thick as HEALY. For me, the high point of the day was the Commandant’s assertion that he is working to ensure the future of the POLAR SEA and POLAR STAR, which have supported US arctic and Antarctic logistics and research since their commissioning in the mid-1970s. In recent years the future of these two ships had been in question, and with it the assurance of US operational capabilities in the heavy ice which is routinely found in the arctic and Antarctic. To top off this good news, the ice persisted throughout the day as we steamed offshore in good weather making for a beautiful sunset.

The sea and ice at sunset.
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North to the Future Mon, 11 Aug 2008 19:46:58 +0000 Phil McGillivary BARROW, ALASKA– “North to the Future” is Alaska’s State Motto. It seems particularly appropriate now with the changes taking place in the north. You fly in to Barrow first via a stop in Fairbanks, and then Dead Horse, the town on the Beaufort Sea coast that supports the oil industry at Prudhoe Bay. The airfield and buildings in Dead Horse are built on raised gravel support beds, above the rivers and pools in the surrounding flat landscape. In one pool at the end of the runway as your plane taxis to take off from Dead Horse a flash of something catches your eye: a single plastic pink flamingo, a fine example of Alaskan humor. I learn that bears have now begun denning in the raised dry airfield gravel beds, so walking around the area near the airport is no longer advisable: my first encounter with an unintended consequence of man’s activities in the north.

It is a short hop by air from Dead Horse on to Barrow. Nok Aker, whose full name, Nokinba, is the Inupiaq word for snowy owl, meets us while we wait for the luggage.

Nok Aker, on the left, and Michael Donovan, on the right.

He is great, maintaining the tradition of the hospitality of the north. In the hours and days that follow we quickly learn that the weather, even now in mid-summer, can change very quickly from pleasant and warm to damp, rainy, windy and bitingly cold. But happily for us, extremely strong winds the preceding days have blown in ice from the open sea, which drifts slowly and beautifully along the gravel beaches of the coast.

Coastal sea ice.

Ice! It is a wonderful sight, and seems to structure the entire ecosystem and community. The locals in Barrow are happy to see the ice too, and launch boats to hunt seals on the ice almost around the clock in the 22 hours of sunlight at this time of year.

The ancient village site of Barrow was known as Ukpiagvik, which means “The Place Where We Hunt Snowy Owls.” Along the beach bluffs the mounded semi-subterranean whale rib and driftwood house beams are visible in the soil where the ancient houses are eroding into the sea.

Welcome to Ukpiagvik.

Ancient house mounds.

Driftwood beams from ancient house eroding into the sea.

Me beside a whale rib house beam sticking out of the ground.

A semi-subterranean house door.

The village of Ukpiagvik was occupied for more than a thousand years, but like many arctic coastal archaeological sites is gradually eroding into the sea. The loss of such important arctic archaeological and cultural heritage sites is exacerbated by rising sea level and increased exposure to spring and autumn storms in the face of decreasing periods of winter coastal ice protection. However, as in the past, the lifestyle of the local people in Barrow remains focused on the resources of the sea: whales, seals, and walrus, and fish, with trips inland to hunt caribou.

The feeling of tradition in Barrow is very strong, we ask questions of all the local people we meet, starting to learn from them about their history and lifestyles. At the Inupiaq Heritage Center we meet the carver of a baleen boat.

Artist Larry Okomailak with his baleen boat.

He is the great-grandson of a Hawaiian who sailed on a whaling vessel to San Francisco in the late 1800s and was shanghai’d on a whaling ship to Alaska, where he stayed to raise a family, whose descendants include this artisan. He is a contemporary example of the historical mix of Barrow traditions that included New England whalers, Hawaiians who came north on whaling vessels (voluntarily or not), and those of the local Inuit. The carver points out that the sail on the baleen boat is multicolored, with stripes of grey, tan, and white. I had noticed it wasn’t the usual black baleen. He explains that colored baleen develops only in old whales: female Bowhead whales must be old enough to have calved at least several times to develop baleen with such colors, and males had to be even older to have baleen with such hues. Bowhead whales (Balaena mysticetus) often live to well over 100 years old, and older whales with such baleen are rarely taken, so it is hard to find such colored baleen to include as the sail of his model boat. With this knowledge suddenly the baleen boat takes on a much greater meaning as a work of art and craft and cultural tradition.

Like many things in Barrow, I continue to realize that just as the mist and fog move in from the ocean and hide the land periodically during our visit, and clear away to reveal the crystalline beauty of the ice, I must look deeper and ask more questions to understand the many and rich traditions here, half revealed and half hidden like the ancient semi-subterranean houses.

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